The present disclosure is related to an electropneumatic positioner for a pneumatic actuator for operating a control device, such as a control valve, of a processing plant, for example a chemical plant, such as a petrochemical plant, a food processing plant such as a brewery, a power plant or the like. The present disclosure also relates to an electropneumatic field device having an electropneumatic positioner and a single-acting or double-acting pneumatic actuator for operating a control fitting, such as a control valve, of a process engineering plant.
German Patent Application DE 10 2012 021 387 B3 describes a generic electropneumatic positioner for controlling a pneumatic actuator of a processing plant. The positioner is connected via a pneumatic piping system to the pneumatic actuator. A housing of the positioner accommodates electrical conductors, pneumatic connection lines and a microprocessor. Via an input on the housing of the positioner, the microprocessor receives a target position signal from a control station of the processing plant. The microprocessor is connected to four plug-in or insertion slots with essentially the same structure that are freely accessible from the outside, which can be optionally occupied by four individual electronic and/or pneumatic components of different designs. The slots are adjusted in a modular fashion so that, depending on which predefined electronic component is inserted, the function of the respective electronic and/or pneumatic component is guaranteed by the establishment of electronic and/or pneumatic communication lines. The slots have pneumatic input interfaces which, via a supply line running within the housing, are supplied in parallel with compressed air via the pneumatic field input of a pneumatic supply source. The slots also include electrical interfaces, which are each connected to a microprocessor via electrical lines. Each slot has an output interface via which output signals either of a pneumatic or electrical kind can be delivered at a respective field device output. Based on the reference position signal received by the microprocessor, the microprocessor transfers electrical signals to an I/P-converter, which forwards a pneumatic output signal to a pneumatic actuator via the assigned field output. In one slot of the field device, for example, an electrical output stage can be used to electrically activate an external solenoid valve arranged outside of the field device housing, for example to effect a forced venting. Compared with known positioners without modular slots, thanks to the above described positioner it is possible for the economic effort for the operator of the process engineering plant in terms of functional adjustment and the design of electropneumatic field devices to be reduced substantially. It has been shown, however, that for some, in particular safety-critical positioner applications, a relatively high configuration effort is still required in the functional adjustment and design of the electropneumatic field device.
The exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.